MEASURE is a study that includes harmonized, pooled data from three cohort sub studies. The purpose is to assess the measurement error properties of diet and physical activity assessment instruments. Common data elements across the three studies include food frequency questionnaires, diet records, 24-hour dietary recalls, accelerometers, anthropometry, demographics resting metabolic rate, physical activity questionnaires, physical activity 24-hour recalls, and biological measures from doubly labeled water and24-hour urine, saliva and fasting bloods. Under a separate contract these data will be harmonized and well-documented with data dictionaries. Support will include the creation of analytic files, variable creation, data linkage and statistical analyses. Analyses may include modeling for calibration/validation and other statistical analyses to assess error in dietary and physical activity assessment methods. Sophisticated statistical analyses for validation and outcome studies may be required.